Multi-hull boat

ABSTRACT

An ocean-cruising V-hull catamaran is disclosed in which the hulls mirror image one another and each have a forward portion longitudinally symmetric with convex curves while the rearward portion of each has a concave, inside curve and said hulls are uniquely wide and high and contain a full-height walkway while said hulls are joined by composite beams.

This Nonprovisonal Application follows a Provisional Application, U.S. PTO No. 60/680832, filed Saturday, May 13, 2005.

FIELD OF THE INVENTION

This invention relates to four new improvements to catamarans of the type designated V-hull cruising catamarans which four improvements cooperate to produce a faster, safer, more comfortable boat. Catamarans, [hereinafter, sometimes “cats”] are an ill-defined ship category. About the only agreement is that a catamaran is a single vessel with two hulls. They may be described according to class, hull shape, and means of propulsion.

First, consider catamarans as being divided into three classes: Coastal, ocean-cruising, and ocean racing.

Coastal cats are small and built to be sailed only near a land mass. A typical one would be the well-known ‘Hobie’ cat. Some are built for day sailing, some are built for racing and some are built for both. Regardless of what they were built for, they are routinely used by their owners for any purpose imaginable. If rigged for sailing, they achieve their highest speeds by heeling over until one hull is out of the water.

Ocean-cruising cats are designed to cruise anywhere with some reasonable degree of comfort while doing so; a trip across the sea should be pleasurable; they are to be suitable for couples, families, etc. If under control, both hulls are always in the water.

Ocean racing cats are designed to be sailed anywhere but comfort is sacrificed as necessary for speed. The only pleasure to be obtained from a trip thereon is victory.

Second, consider catamarans described by hull shape; hull shape may be described according to the plan view of the hull at deck level and vertical cross-section[s] perpendicular to the hull centerline.

The plan view of the hull at deck level has an inboard side and an outboard side of any configuration.

The vertical cross section may be simple, e.g., circular, U-shaped, V-shaped, etc., or convoluted into any shape imaginable. One cat may have several different cross sectional shapes although, normally, one hull is the mirror image of the other.

Third, the method of propulsion may be motor, sail or both.

BACKGROUND OF THE INVENTION

Prior to this invention, all catamaran hull shapes in plan view at deck level were composed of either a convex curve or curves or a convex curve with a straight line. Most were longitudinally symmetric. [E.g., the hulls shown in U.S. Pat. Nos. 2,106,432—see FIG. 3, 4,002,133—see FIG. 2 and 4,498,409—see FIG. 6.] Many were symmetric both longitudinally and bow/stern [with the exception of the bow point and the stern point]. Others were totally asymmetric and longitudinally the convex curves didn't match with the larger radius curve being inboard. [E.g., the hull shown in U.S. Pat. No. 2,585, 599, FIG. 7. Note therein a convex curve in the cross-sectional hull shape {FIG. 6}, but not in the plan view.]

Prior to this invention, although most cruising catamarans hulls' cross-sectional shape perpendicular to the hull centerline was U-shaped and most of the living space is contained in a cabin above and between the hulls, there were catamarans whose hulls' cross-sectional shape perpendicular to the hull centerline was V-shaped and had no cabin between the hulls; their hull is described as a ‘V-hull’. ‘V-hull’ is elsewhere applied to hulls having little in common with the letter ‘V’ [e.g., see DVH-184—a ‘V-hull’ power boat]. In prior art, V-hull catamarans have been made of ribs each of which is a simple V-shaped rib

Prior art cats were powered by any means.

The shortcomings of the existing art are many and well known. All existing catamarans suffer from ‘underwing slamming’. This is a condition where waves rise between the hulls and slap the supporting structures. In ocean-cruising catamarans, particularly the majority which have the cabin between the hulls, such structures are over or adjacent to the sleeping quarters. Underwing slamming is just one of the problems caused by the path of the water flowing between the hulls. The water path also slows the vessel and/or reduces the comfortable and/or safe cruising speed.

All non-V-hull catamarans, must use daggerboards, keels or some keel substitute. If a keel device is impacted, it can tear out a big hole in the hull.

Non-V-hull ocean cruising cats with the center cabin are quite prone to capsizing.

All catamarans are also prone to connecting beam failure which can be catastrophic.

Prior art V-hull catamarans feature narrow hulls which are too small to provide a comfortable living area. For many years, they have been essentially abandoned as a proper cruising boat. Finally, below-deck, traveling the length of a hull, if at all possible, requires ducking through portals, stepping over the portal stoop and often turning sidewise when doing so while moving past the ribs of the boat.

BRIEF SUMMARY OF THE INVENTION

It is the general object of the invention to provide an improved ocean cruising catamaran being faster, safer and more comfortable than existing art. A further object of the present invention is to provide an improved V-hull cat wherein the hull shape channels the water between the hulls to provide a smooth, flat, inter-hull water surface for improved comfort and speed. A still further object, is to provide an improved V-hull cat wherein the hull shape provides adequate living space within the hulls and a full height passageway through the hull exists. Finally, yet another object of the present invention is to provide an improved design for the beams which connect the hulls. All improvements cooperate to produce a faster, safer, more comfortable boat.

This invention eliminates underwing slamming by channeling the water flow between the hulls into a smooth, level, river-like flow. This is accomplished by constructing the hulls with asymmetric hull curves at deck level featuring a concave/convex curve on the interior side of the hull. This eliminates the rough water flow that causes underwing slamming. Not only does this feature of the invention eliminate underwing slamming, but it also yields a smoother, more comfortable and faster ride.

This invention dramatically reduces the possibility of failure of the hull connecting system by using stronger, smaller, ‘composite’ beams. Composite beams have at least two meanings: the classic meaning is a beam which conjoins diverse materials such as wood and steel. More recently, a composite beam is one which is made of one or more materials which are composites themselves—normally materials of recent invention. These beams are often referred to as ‘hi-tech’. This invention uses classic composite beams. They are fiberglass coated wood-steel composite beams joined as desired. The composite beams, having less wind resistance, cooperate with the smooth water flow created by the hull shape at deck level to make this invention faster [the smaller beam reduces wind drag] and safer and more comfortable [the smaller beam simplifies and enhances movement aboard the invention].

The next innovation of this invention is the fabrication of a wider V-hull. The hull of this invention, at its widest, is approximately 50% wider and 15% higher than existing art. The existing art uses a narrow hull because the plywood sheeting used to cover the hull, cannot be bent to fit to the hull using only body strength. Methods to enhance body strength are not used. This invention uses such methods.

The final innovation of this invention available by cooperation with the wider hull of the invention is the free-walking doorways through the bulk-head ribs of the main cabin.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective drawing of the preferred embodiment of the invention.

FIG. 2 is a diagrammatic front view of the preferred embodiment of the invention.

FIG. 3 is a diagrammatic view, in cross section, of a connecting beam of the preferred embodiment of the invention [fiberglass covering is not shown].

FIG. 4 shows diagrammatically a typical, symmetric, V-shaped rib for the hull of the preferred embodiment of the invention.

FIG. 5 shows diagrammatically this invention's asymmetric, V-shaped rib.

FIG. 6 shows a simple method of applying the innovation of using external force in the application of the plywood sheets so that the wider hull of the invention can be covered.

FIG. 7 is a diagrammatic view of a typical mid-hull rib within the cabin of this invention showing the walkway aperture receiving the walkway base, portside surface and starboard surface in perspective [floor level indicated, but floor not shown for simplicity].

PREFERRED EMBODMENT

Referring now to the drawings, FIGS. 1 and 2 illustrate the invention. They show V-hulls 8, and connecting beams 9 and, diagrammatically, FIG. 1 shows, for each hull, a curve of the hull at deck level 10. By following the hull's forward, symmetric ribs 11, see FIG. 4, with a single, final asymmetric rib 12, see FIG. 5, said curve is formed. Said asymmetric rib 12 may be formed with various degrees of asymmetry. The amount of asymmetry affects the smoothness of the water flow between the hulls, the speed of the preferred embodiment and the volume of hull 8 at the asymmetric rib 12. The preferred embodiment is a compromise of those variables. It seeks to obtain the desired effect with minimum effect on the volume of the hull 8. FIG. 5 diagrammatically illustrates the type and style of the asymmetry used. The amount of asymmetry, dimension a, is exaggerated in FIG. 5 for clarity. In actuality, the amount of asymmetry is such that dimension a is approximately 1/14^(th) of the total width of the rib without the asymmetry; stated otherwise, in actuality, the asymmetric leg 1 of the asymmetric rib is approximately of the ratio of 6:7 to the symmetric leg 2 of the asymmetric rib. It is the immediate juxtaposition of the final symmetric rib, a rib such as rib 11, followed by the asymmetric rib 12 that creates said curve 10 in the preferred embodiment.

Said beams 9 are ‘composite’ beams. The essential portions of the preferred embodiment thereof are shown in FIG. 3. Said portions are a steel tube 4 cemented on top of a laminated wood portion 3 with epoxy 5 which may be bodied but in the preferred embodiment is not. The actual preferred embodiment of the beam is coated with fiberglass in any appropriate fashion and painted; said fiberglass/paint is not shown

FIG. 6 illustrates the method used in the preferred embodiment to apply additional external force to the sheets of plywood 7 so that a wider V-hull can be formed. The external force is applied using lever arms 6 attached to the plywood sheet 7 by any convenient means. Of course, in mass production, the production method for the invention would reflect more capital cost.

FIG. 7 shows a diagrammatic version of a non-solid bulkhead 17 showing, in perspective, the walkway U-channel 20 comprised of the base 13 and the starboard surface 19 and the portside surface 18. The top of the walkway U-channel 20 is at the floor level 15—the floor, itself, is not shown for reasons of clarity. As can be seen, a non-solid bulkhead 17 contains a doorway 14. Non-bulkhead ribs [not shown] do not have a doorway; they only have the floor level 15 and the walkway U-channel 20 aperture. Said doorway is high enough so that one need not stoop to pass through it while walking on the walkway base 13.

Those skilled in the art will appreciate that various adaptations and modifications of the preferred embodiment can be configured without departing from the scope and spirit of the invention. It is to be understood that the invention may be practiced other than as specifically described herein, within the scope of the appended claims. 

1. A catamaran having at least a first and second hull, with at least one hull being formed to have: a walkway level.
 2. The catamaran of claim 1 wherein the walkway level further comprising: a walkway U-channel being formed by a walkway base, a portside surface, and a starboard surface all being supported adequately.
 3. The catamaran of claim 2 wherein said adequate support is provided by: at least one rib having: a walkway aperture for receiving said walkway U-channel.
 4. A catamaran having at least a first and second hull, each hull being substantially identical in their respective external shapes, joined to be mirror images one of the other, each hull being formed to have: a substantially triangular cross section, the cross sectional shape extending substantially along the entire length of the hull, the substantially triangular cross section being defined by a plurality of v-shaped ribs having: an outer side and an inner side, the outer and inner sides meeting at a keel, the outer side of the v-shaped ribs being covered to form a convex surface, the inner side of a number of the v-shaped ribs at a forward portion of the hull being covered to form a convex surface, and the inner side of the remaining number of v-shaped ribs at the rear portion of the hull being covered to form a concave surface.
 5. The catamaran of claim 4, in which the concave portion of the rearward portion of the hull is formed by: a final, asymmetric rib wherein the asymmetric rib is further comprised of an inner side whose angle with the keel is less, as measured by degrees from a vertical centerline plane of the hull, than the outer side.
 6. A catamaran having at least a first and second hull, each hull being substantially identical in their respective external shapes, joined to be mirror images one of the other, each hull being formed to have a substantially triangular cross section, the cross sectional shape extending substantially along the entire length of the hull, the substantially triangular cross section being defined by a hull framework whereby forming a hull of expanded volume.
 7. The catamaran of claim 6, wherein said hull framework is formed by at least one of the centrally located ribs having an included angle of approximately ±150 or more as measured from the vertical centerline of the rib.
 8. The catamaran of claim 6, wherein said hull framework is formed by: at least one of the centrally located ribs having a height in excess of 7′.
 9. The catamaran of claim 8, wherein at least one of the centrally located ribs has an included angle of approximately ±150 or more as measured from the vertical centerline of the rib.
 10. A catamaran having at least a first and second hull wherein the hulls are joined by: at least two connecting beams, at least one of which beams may be designated as a ‘composite’ beam.
 11. The catamaran of claim 10 wherein the ‘composite’ beam is a steel-wood composite held together as appropriate.
 12. The catamaran of claim 11 wherein the steel-wood composite beam further comprises: a steel tube joined as appropriate to laminated wood.
 13. The catamaran of claim 12 wherein the appropriate method of joining further comprises: any appropriate epoxy, bodied or otherwise.
 14. The catamaran of claim 2 wherein said adequate support is provided by: at least one rib having: a walkway aperture for receiving said walkway U-channel in combination with the catamaran of claim 4, in which the concave portion of the rearward portion of the hull is formed by: a final, asymmetric rib wherein the asymmetric rib is further comprised of an inner side whose angle with the keel is less, as measured by degrees from a vertical centerline plane of the hull, than the outer side.
 15. The catamaran of claim 2 wherein said adequate support is provided by: at least one rib having: a walkway aperture for receiving said walkway U-channel in combination with the catamaran of claim 8, wherein: at least one of the centrally located ribs has an included angle of approximately ±150 or more as measured from the vertical centerline of the rib.
 16. The catamaran of claim 2 wherein said adequate support is provided by: at least one rib having: a walkway aperture for receiving said walkway U-channel in combination with the catamaran of claim 12 wherein the appropriate method of joining further comprises: any appropriate epoxy, bodied or otherwise.
 17. The catamaran of claim 4, in which the concave portion of the rearward portion of the hull is formed by: a final, asymmetric rib wherein the asymmetric rib is further comprised of an inner side whose angle with the keel is less, as measured by degrees from a vertical centerline plane of the hull, than the outer side in combination with the catamaran of claim 8, wherein: at least one of the centrally located ribs has an included angle of approximately ±150 or more as measured from the vertical centerline of the rib.
 18. The catamaran of claim 4, in which the concave portion of the rearward portion of the hull is formed by: a final, asymmetric rib wherein the asymmetric rib is further comprised of: an inner side whose angle with the keel is less, as measured by degrees from a vertical centerline plane of the hull, than the outer side in combination with the catamaran of claim 12 wherein the appropriate method of joining further comprises: any appropriate epoxy, bodied or otherwise.
 19. The catamaran of claim 8, wherein: at least one of the centrally located ribs has an included angle of approximately ±150 or more as measured from the vertical centerline of the rib in combination with the catamaran of claim 12 wherein the appropriate method of joining further comprises: any appropriate epoxy, bodied or otherwise.
 20. The catamaran of claim 2 wherein said adequate support is provided by: at least one rib having: a walkway aperture for receiving said walkway U-channel in combination with the catamaran of claim 4, in which the concave portion of the rearward portion of the hull is formed by: a final, asymmetric rib wherein the asymmetric rib is further comprised of: an inner side whose angle with the keel is less, as measured by degrees from a vertical centerline plane of the hull, than the outer side and further in combination with the catamaran of claim 8, wherein: at least one of the centrally located ribs has an included angle of approximately ±150 or more as measured from the vertical centerline of the rib.
 21. The catamaran of claim 2 wherein said adequate support is provided by: at least one rib having: a walkway aperture for receiving said walkway U-channel in combination with the catamaran of claim 4, in which the concave portion of the rearward portion of the hull is formed by: a final, asymmetric rib wherein the asymmetric rib is further comprised of: an inner side whose angle with the keel is less, as measured by degrees from a vertical centerline plane of the hull, than the outer side and further in combination with the catamaran of claim 12 wherein the appropriate method of joining further comprises: any appropriate epoxy, bodied or otherwise.
 22. The catamaran of claim 4, in which the concave portion of the rearward portion of the hull is formed by: a final, asymmetric rib wherein the asymmetric rib is further comprised of: an inner side whose angle with the keel is less, as measured by degrees from a vertical centerline plane of the hull, than the outer side in combination with the catamaran of claim 8, wherein: at least one of the centrally located ribs has an included angle of approximately ±150 or more as measured from the vertical centerline of the rib and further in combination with the catamaran of claim 12 wherein the appropriate method of joining further comprises: any appropriate epoxy, bodied or otherwise.
 23. The catamaran of claim 2 wherein said adequate support is provided by: at least one rib having: a walkway aperture for receiving said walkway U-channel in combination with the catamaran of claim 4, in which the concave portion of the rearward portion of the hull is formed by: a final, asymmetric rib wherein the asymmetric rib is further comprised of: an inner side whose angle with the keel is less, as measured by degrees from a vertical centerline plane of the hull, than the outer side and further in combination with the catamaran of claim 8, wherein: at least one of the centrally located ribs has an included angle of approximately ±150 or more as measured from the vertical centerline of the rib and finally in combination with the catamaran of claim 12 wherein the appropriate method of joining further comprises: any appropriate epoxy, bodied or otherwise. 